No. The Customers list search box only matches user ID, name, last name, email and phone — the Membership ID field is not included, and the customer list's columns (name, role, email, phone, status, last checkout, lifetime value, balance, notes, one-time fee) do not include Membership ID either. To find a customer by their Membership ID you need to open each candidate profile and check the field manually, or ask Sprwt support for a data pull.